The Colorado Oil and Gas Conservation Commission had nine teams on the ground inspecting the flood plains, and assessed 157 wells and 71 tank batteries on Monday. The agency is now tracking 11 notable releases or spills from operations that have been inspected in the last several days, reaching a total of 822 barrels, with amounts for two of the releases unknown.

Todd Hartman, spokesman for the state Department of Natural Resources, which oversees the COGCC, said that on Monday, officials reported a Noble Energy location east of Kersey near U.S. 34 and U.S. 56 released 5,082 gallons of oil; a PDC Energy location east of Greeley near U.S. 34 and U.S. 34 bypass released 2,520 gallons; and a Mineral Resources location north and west of LaSalle released an unknown amount.

The COGCC has stated that operators are required to clean up all spills, “recognizing that contaminants of all kinds have been moved and dispersed with floodwaters. These conditions will create challenges in certain cases with tying impacted areas to specific parties, but operators will be accountable for cleanup when appropriate and when possible.”

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While the new estimate of oil released from flood-damaged tanks has grown to almost 35,000 gallons, officials believe it really is just a minute part of a much bigger problem.

Floodwaters quickly became a toxic soup of wastewater, raw sewage, industrial and household chemicals, agricultural waste and chemicals rushing downstream. Oil and gas releases, officials said, have been so small it’s almost immaterial.

“There were likely hundreds of millions of gallons of untreated or partially treated sewage, and that is the larger public health concern,” said Mark Salley, spokesman for the state Department of Public Health and Environment. “It doesn’t mean the state health department is not concerned about chemical releases from oil and gas or ag or other industries or homes, but the bigger public health concern is the sewage that can make people sick.”

Oil and gas operators have had teams on the ground and in the air surveying the damage to their sites for days, reporting spills immediately to the authorities.

As of Tuesday, the Colorado Oil and Gas Conservation Commission was following 11 notable spills totaling 34,524 gallons of oil spilled from storage tanks.

In context, that amount lost was essentially washed away in a half second along the fast-moving South Platte River, said Ken Carlson, an associate professor of civil and environmental engineering with Colorado State University.

Carlson explained that the South Platte essentially was passing 10,000 cubic feet per second downstream for days, which is roughly 75,000 gallons per second.

“If this happened a month ago and (river) flows were normal, and we had a spill of 35,000 gallons, that would be a serious situation,” Carlson said. “In the context of a natural disaster, it’s just one more problem that occurred because of it.”

As crews inspected tanks in the field, many realized through damage and computer records that in some cases, the oil was no longer there, even after shutting in almost 1,500 wells prior to the flooding. But it’s not as if they found standing pools of goo, Carlson said.

“They happened during the height of the flood. It’s not like all of the sudden the flood-damaged stuff is now starting to leak,” Carlson said.

Carlson said the dilution of the oil and other toxins has made this disaster somewhat manageable when compared to spills like the BP spill in the gulf, or the Exxon Valdez off the coast of Alaska years ago. In those cases, the oil was dense and deposited in a relatively small space ­— so it stuck around. Niobrara crude, Carlson said, is light.

“Dilution is one of the more important environmental approaches for dealing with pollution, and there’s just a tremendous amount of dilution here,” Carlson said. “If it was 35,000 gallons sitting in the South Platte now, it would be huge. The fact that it was diluted so quickly probably lessens the environmental impact it will have.”

Carlson said he’s not terribly concerned with how the polluted waters will affect groundwater, given there’s enough barriers between the surface and the aquifer most in rural Weld drink from.

Mark Wallace, director of the Weld County Department of Public Health and Environment, said the county is still offering free water well testing if residents are concerned about their groundwater.

He said the county is on the ground with regulators and surveyors and, as operators turn wells back on, it’ll be controlled. He said he has little concern over long-lasting damage.

“For the most part, what we’re finding, is long term, from floods in other parts of the country, it doesn’t do long-lasting damage,” Wallace said.

Many of the tanks were in the floodplains, but not in the immediate areas of the banks, and they were designed to withstand typical flooding. Few could have predicted the waters would rise as they did. The South Platte, as an example, floods at 10 feet, and waters hit 19 feet at their peak.

Still, it will start a discussion on whether oil and gas facilities should be located in the floodplain.

“It is problematic,” said Sara Barwinski, of Weld Air and Water, a group of residents who monitor oil and gas operations in the city of Greeley and Weld County.

“Part of it goes back to the bigger picture. Balanced development means paying attention to where you put oil and gas, not that it doesn’t have a role to play in our economy. But we don’t think that’s in floodplains, or near schools or next to neighborhoods.”

If this happened a month ago and (river) flows were normal, and we had a spill of 35,000 gallons, that would be a serious situation. In the context of a natural disaster, it’s just one more problem that occurred because of it. — Ken Carlson, CSU associate professor